This section provides background information related to the present disclosure which is not necessarily prior art.
In an optical module product, when finding that front end light is less than a LOS threshold, a receiver chip will send a LOS-ASSERT alarm, and a LOS pin of the receiver chip is usually a high level of a digital signal; when the front end light changes from being less than the alarm threshold to being greater than the alarm threshold and exceeds a DEASSERT threshold set for the chip, the receiver chip will return to a LOS-DEASSERT state, and the LOS pin of the receiver chip is usually configured as a low level of the digital signal. This LOS state will be output to a system through a LOS output interface (LOS pin) of the optical module, the system only reads the state of the optical module at this LOS pin usually, and the LOS pin can only output a function of a LOS-ASSERT or LOS DEASSERT state signal of the module to the system, and does not have other functions.
In some special cases, it is required to add some functions at a module when a LOS signal appears, so that the system can not only read the state of the module through the LOS pin but also transfer a power shut instruction to the module through a newly defined pin. For example, after responding to a LOS-ASSERT signal, the system will respond to a power shut instruction (RX-POWER SHUT) of a power supply of the receiver chip, or a power shut instruction (POWER SHUT) of a general power supply in an ideal case, so as to perform power cut on a receiving end of the module or the entire power supply.